For acquisition of especially large quantities of test signals whose meaning content goes beyond traditional physical quantities such as current, voltage and temperature, it has been customary in the past to use complex and specially assembled measurement arrangements. This is the case in particular when the test signals picked up by an industrial routine or an industrial device must be reprocessed, compiled and analyzed according to special strategies.
Such a case also occurs in acoustic diagnosis of test objects. In particular in the manufacture of machines and equipment having moving or rotating subcomponents, it is customary to perform routine acoustic testing or diagnosis in a test field. Such machines and equipment may include motors, generators, turbines or even vacuum cleaners, fans and many other items. Microphone-like vibration or acceleration sensors, for example, are mounted at one or more selected points on a test object, e.g., in the area of bearings, drives or shafts. A number of technical conclusions can be drawn from the acoustic and mechanical vibrations picked up and the structure-borne noise. For example, it is possible to determine the manufacturing quality of a test object or simulate actual values characterizing the condition of the production facilities used. Furthermore, it is possible to observe the manufacturing tolerances of known influencing quantities, wear-related phenomena and much more.
In acoustic testing and diagnosis of technical objects, it is also common to use powerful special hardware components to tie the test signal sensors to computerized devices that perform the analysis of the measured values.
An object of the present invention, is to provide an acquisition device for analog test signals which occur in the acoustic diagnosis of technical test objects, without requiring any special instrumentation if possible.
The present invention has the advantage that standard components can be used for test signal acquisition. This is achieved in particular with the device according to the present invention by the fact that the individual interface areas available are used in a controlled manner for implementation of technical subfunctions in test signal acquisition as part of the acoustic diagnosis with a standard device, e.g., one referred to informally as a personal computer. Thus, first standard external interfaces, preferably standard parallel interfaces of the computer are used, also fitted with standard interface cards, to digitize the analog test signals from vibration and acceleration sensors and enter them into the computer.
The object of controlling the test signal pick-up, i.e., in particular program-controlled switching of the test signal acquisition on and off, and preferably the control of optionally additional time-coordinated automatic handling operations with the respective test object and in its environment, is achieved by using second standard external interfaces of the standard computer. This is preferably standard serial interfaces of the standard computer. The usual interface provided for connecting a printer is especially suitable for this purpose. However, the interface usually provided for connecting an input device known conventionally as a mouse or a game port may also be used for this purpose. Trigger signals generated by at least one external switching means are entered into the computer via this interface, specifying the beginning and end of test signal acquisition. However, such trigger signals may also be output over the interface from the second area, for example, to control automatic manipulators acting on the test objects or automatic conveyor devices in a time-coordinated operation.
The use of the areas of external interfaces present in a standard computer for digitizing the test signals and for separate exchange of controlling trigger signals as proposed according to the present invention makes it possible to use standard computer hardware and in particular standard interface cards for analog-digital conversion of the analog test signals supplied by the vibration and acceleration sensors. It has surprisingly been found that interface cards can be used in a first area on an external interface designed for digital processing of vibrations of the respective test object approximately in the audible frequency range. Such interface cards may be standard hardware modules known as sound cards which are generally used for acoustic reproduction of digital speech and music information stored in the memory of the computer, i.e., for digital-analog conversion of corresponding digital files.